六种凝集素受体在星形细胞瘤的表达研究

用麦胚凝集素（WGA）、扁豆凝集素（LCA）、花生凝集素（PNA）、马铃薯凝集素（STL）、双花扁豆凝集素（DBA）、荆豆凝集素（UEA－1）作为分子探针对26例星形细胞瘤进行组织化学杂色标记，观察其凝集素受体的表达，发现WGA、LCA阳性率较高，PNA、STL的凝集素受体表达阳性率次之，其中LCA、STL对分级有一定帮助；DBAUEA－1的阳性率极低，对于星形细胞瘤的诊断意义不大，但是UEA－1对脑血管疾患及血管源性的肿瘤的研究有较大意义。可见，凝集素对于颅内胶质瘤的诊断和鉴别诊断、分级及分型有重要意义．     

VEGF treatment induces signaling pathways that regulate both actin polymerization and depolymerization

The angiogenic growth factor vascular endothelial growth factor (VEGF) enhances endothelial cell migration through the activation of multiple signaling transduction pathways. Actin reorganization is an important component in VEGF-induced migration, yet the signaling pathways mediating this process remain unclear. Actin reorganization involves both actin polymerization and depolymerization, and in this study we demonstrate that VEGF-treatment regulates both of these activities. With respect to actin polymerization, our results indicate that the actin nucleation promoting factors (NPF) neural Wiskott–Aldrich syndrome protein (N-WASP) binds the SH2- plus SH3-domain containing adaptor protein Nck in both control and VEGF-treated cells. We had previously showed that VEGF treatment leads to the recruitment of Nck to activated receptor, and our current results indicate a VEGF-dependent redistribution of N-WASP to the cell surface. A Nck dominant-negative blocked Nck recruitment to receptor, blocked N-WASP cellular redistribution and attenuated actin stress fiber formation. With respect to actin depolymerization, VEGF-treatment led to the rapid phosphorylation of the actin depolymerization factor cofilin, and its upstream regulator, LIM-kinase (LIMK). Unlike what is observed in certain other cell types, the p21-activated kinase (PAK), a Nck binding protein, does not mediate VEGF-induced LIMK phosphorylation, as a PAK dominant-negative had no effect on this activity. The PAK dominant-negative also did not affect VEGF-induced actin reorganization. Pharmacological inhibitors of phosphoinositide-3 kinase (PI3-K) and the rho-activated kinase (ROCK) attenuated VEGF-induced LIMK phosphorylation, indicating a role for (PI3-K) and ROCK in the signaling pathways leading to regulation of LIMK activity.